Furnace



Aug- 13, 1929- A. SMALLWOOD ET AL FURNACE Filed April 20, 1920 a Sheets-Sheet 1 I 1 1 H// I I I I g- 1929- A. SMALLWOOD El AL FURNACE Filed April 20, 1926 3 Sheets-Sheet 3 Sheets-Sheet 3 Aug. 13, 1929. A. SMALLWOOD ET AL FURNACE Filed April 20, 1926 Patented Aug. 13, 1929.

UNITED STATES PATENT OFFICE.

ALFRED SMALLWOOD AND JOHN FALLON, OF SMETHWICK, ENGLAND.

FURNACE.

Application filed April 20, 1926, Serial No. 103,327, and in Great Britain April 29, 1925.

by the waste gases, wherein the air for combust-ion is adapted to descend within a preheated conduit to support the combustion of fluid fuel, and in which the furnace is of a vertical character wherein the pre-heating of the air for combustion takes place in the vertical portion of the system while the admixture of the air with the fuel, the combustion thereof and the application of the resultant heat to the goods, occurs in the lower part of the furnace.

The present invention comprehends a furnace of this type which is characterized in that the flame or furnace gases resulting from the combustion of the fuel by virtue of the pre-heated air is or are adapted to pass directly into the heating chamber. In addition we arrange that the furnace gases utilized for pre-heating the air for combustion are adapted, after passing from the said heating chamber, to envelop a primary combustion chamber containing the burner proper, which primary combustion chamber is of transverse capacity exceeding that of the down-draught of the air for combustion; this primary combustion chamber advantageously converges in a direction towards the mouth at which it emits the flame or furnace gases for application to the heating contained in the goods chamber.

The heating flame may be'adapted to be projected downwardly upon the goods to be treated by virtue of a drau ht which may be created either or both by a an, blower or the like, and/or by the upflow of the waste gases within a conduit or conduits located in positions, one on each side of the down draught conduit in which the air for combustion is pro-heated. The down-draught conduit for the air for combustion may be separated from the conduits conveying the waste gases by partitions composed of carborundum or other material of high or suitable heat conductivity.- Dampers may be provided at the upper extremities of the waste gas conduits for the purpose of providing for the control of the draught and the general working of the furnace.

The furnace may be of a composite character incorporating an arrangement wherein a division occurs in the lower partof the furnace so that there may be a lower portion constituting the furnace proper and an upper portion constituting the recuperator system proper.

In order that this invention may be clearly understood and readily carried into practice reference may be had to the appended drawings on which Figure 1 illustrates in vertical section an embodiment of the present invention.

Figure 2 illustrates in vertical section the lower part of a furnace according to a modifled embodiment of the present invention.

Figure 3 is a sectional plan of the furnace shown in Figure 2.

Figure 4 is a view similar to Figure 2, but showing a still further modification of the invention.

Figure 5 is a sectional plan of the furnace shown in Figure 4.

In a convenient embodiment of the present invention as shown in Figure 1 the fuel is introduced by a gas or oil fuel burner a located in an enlarged part of the lower portion of the pre-heated air conduit 6, and such lower portion of the said conduit may terminate in a constricted mouth 0 located above the crucible or receptacle proper in which the goods are treated. The gas or oil fuel burner may take the form of a horizontal conduit having, a series of perforations at its underside, and the downward convergence or curvature of the walls of the combustion chamber may serve to direct or concentrate the air towards or in the vicinity of the series of orifices.

The structure may be sub-divided in its lower region as for instance at the level a: so that there is a lower portion constituting the furnace proper and an upper portion constituting the recuperator system proper. It may, however, be desirable additionally or alternatively to sub-divide the furnace proper as for instance at the level at which the mouth of the primary combustion chamber occurs. These proposals permitting of the sub-division offer advantages as for instance to permit of inspection and repair.

Advantageously we employ a central rectangular conduit 1) for the down-draught of the pre-heated air and two rectangular conduits d d, one on each side, for the rip-draught of waste gases. The centre conduit is separated from the outer conduits by part1- tions 6 e of carborundum or other material of high or suitable heat conductivity, and the draught and general working of the furnace v of the waste gas conduits (Z. \Vhen a waste gas conduit is provided on each side of the central air conduit the flame emitted from the bottom of the latter may divide laterally and the waste gases may ascend substantially in equal quantities on the respective side flues which may diverge downwardly towards the mouth of the crucible or other receptacle in which the goons are treated. tion of the apparatus may be composed of an outer wall 9' of brickwork in which the carborundum or other partitions may suitably be incorporated and said stack portion may be interchangeable with separate crucibles or other plant containing goods to which the heat treatment afforded by the present invention is to be applied.

The system may be applied in multiple for long furnaces. It also may be supplied with an additional conduit or downshaft for pre-heating the fuel in which case the air and fuel conduits may merge in order to mix the fuel before delivery from the down-draught pressure system to the chamber.

Any appropriate charging or inspection openings may be provided in connection with the lower part of the furnace as illustrated, and in view of the up-draught created by the channels d it is possible to utilize an open aperture in connection with the working chamber if desired. I

The embodiment illustrated in Figure 2 differs from that shown in F igure 1 in that the flame heating gases is or are adapted to be directed laterally into the working chamber 7c, the fluid fuel burner a being in this embodiment located vertically within a combustion chamber, the mouth of which converges in a horizontal direction as shown in Figure 3. The ascending waste gas passages d and the air passage 1) are diverted angularly as shown in Figure 2 with the result that while the furnace is still characterized by the vertical draught system wherein the air for combustion is heated by the waste gases, the flame is nevertheless projected laterally. in the case shown in Figures 2 and 3 into an ppen hearth'chamber of the reverberatory The embodiment shown in Figures 4 and 5 differs from that illustrated in Figures 2 and 3 in the fact that the working chamber Z2 is utilized for containing crucibles, the flame or furnace gases being limited laterally at a? from the primary combustion chamber which is enveloped by the passages Z (Z for The stack por the waste gases, these passages being diverted at right angles and adapted to ascend one on each side of the central passage for the air which in its lower part containsa horizontal burner a adapted to produce the flame or furnace gases which are subsequently emitted at 0 Having described our invention what we claim and desire tosecure by Letters Patent 1s l. A furnace of the class described having a primary combustion chamber, a burner in said chamber, an air conduit leading downwardly to said chamber and at its lower end discharging air thereunto, a heating chamber into which said primary combustion chamber directly discharges both air and the flame from said burner and an upwardly directed waste gas conduit leading from said heating chamber, said conduits bein in proximity to each other so that the partition wall between them is heated by the waste gas and serves to heat the air prior to its introduction to the combustion chamber.

2. A furnace of the class described having a primary combustion chamber, a burner in said chamber, an air conduit leading downwardly to said chamber and at its lower end discharging air thereunto, a heating chamber into which said primary combustion chamber directly discharges both air and the flame from said burner and an upwardly directed waste gas conduit leading from said heating chamber, said conduits being in proximity to each other so that the partition wall between them is heated by the waste gas and serves to heat the air prior to its introduction to the combustion chamber and a damper to regulate the escape of waste gas from the waste gas conduit;

3. A furnace of the class described having a primary combustion chamber, a burner in said chamber, an air conduit leading downwardly to said chamber and at its lower end discharging air thereunto, a heating cham- 

